Method and system for broadcasting digital audio and video to an analog wireless device

ABSTRACT

An audio input interface ( 122 ) receives a digital audio signal and identifies an audio bitstream which is optionally decrypted by a decryption unit ( 123 ), and decoded by an audio decoding unit ( 124 ). An audio digital to analog converter ( 126 ) converts the decoded audio bitstream to an analog audio signal which is optionally decrypted by an audio analog decryption unit ( 127 ). A video input interface ( 142 ) receives a digital video signal and identifies a video bitstream which is optionally decrypted by a video digital decryption unit ( 143 ), and decoded by a video decoding unit ( 144 ). A video digital to analog converter ( 146 ) converts the decoded video bitstream to an analog video signal that is optionally decrypted by a video analog decryption unit ( 147 ). An analog transmitter ( 150 ) mixes the analog audio signal and analog video signal and transmits an analog wireless output signal to an analog wireless device ( 110 ).

RELATED U.S. APPLICATION DATA

Continuation of Ser. No. 09/071,045, filed May 4, 1998, now issued asU.S. Pat. No. 6,335,768.

The present invention is related to the following inventions which areassigned to the same assignee as the present invention:

Method and System for Distributing Digital Audio and Video to an AnalogWireline Device, filed May 4, 1998, having Ser. No. 09/071,046.

Method and System for Broadcasting/Distributing Digital Audio and Videoto a Television, filed May 4, 1998, having Ser. No. 09/071,368.

Method and System for Broadcasting Digital Audio to a Radio, filed May4, 1998, having Ser. No. 09/071,047.

FIELD OF THE INVENTION

The present invention relates generally to digital audio and video.

BACKGROUND OF THE INVENTION

A wide variety of digital audio and video content currently exists. Forexample, computers can process or store audio and video data obtainedvia the internet and other sources. Consumption of digital audio andvideo is currently confined, however, to devices designed to accept aspecific form of input. For example, a computer can play digital audioand video provided in a specific digital format which the computer isconfigured to process, but a current television cannot play the samedigital audio and video data because it is designed to receive anentirely different form of input. Accordingly, it would be desirable tohave the capability of playing digital audio and video with devicesdesigned to receive a different form of input.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of a system for broadcasting audio and videoto an analog device;

FIG. 2 is a flowchart of the process performed by the system shown inFIG. 1;

FIG. 3 is a flowchart of the process for processing a digital audiosignal;

FIG. 4 is a flowchart of the process for processing a digital videosignal; and

FIG. 5 is a flowchart of the process for outputting the digital audioand video to the analog device.

DETAILED DESCRIPTION OF THE DRAWINGS

In a preferred embodiment of the invention, a method and system isprovided for broadcasting digital audio and/or video to an analogwireless device. More specifically, the preferred embodiment of theinvention obtains digital audio and/or video signals and broadcasts theaudio and/or video content of the digital signals to the analog wirelessdevice. As a result, an analog wireless device which is not designed toreceive digital audio or video can play the audio and/or video content.

In one aspect of the preferred embodiment, an audio circuit broadcastsan analog audio signal to the analog wireless device. An audio inputinterface receives a digital audio signal and identifies an audiobitstream. Optionally, an audio digital decryption unit decrypts theaudio bitstream. An audio decoding unit then decodes the audiobitstream. The audio decoding unit optionally includes a decompressioncomponent decompressing the audio bitstream. An audio digital to analogconverter converts the decoded audio bitstream to an analog audiosignal. Optionally, an audio analog decryption unit decrypts the analogaudio signal. An analog transmitter transmits the analog audio signal tothe analog wireless device.

In another aspect of the preferred embodiment, a video circuitbroadcasts an analog video signal to the analog wireless device. A videoinput interface receives a digital video signal and identifies a videobitstream. Optionally, a video digital decryption unit decrypts thevideo bitstream. A video decoding unit then decodes the video bitstream.The video decoding unit optionally includes a decompression componentdecompressing the video bitstream. A video digital to analog converterconverts the decoded video bitstream to an analog video signal.Optionally, a video analog decryption unit decrypts the analog videosignal. An analog transmitter transmits the analog video signal to theanalog wireless device.

In yet another aspect of the preferred embodiment, the audio circuit andvideo circuit are combined to broadcast an analog wireless output signalcontaining both audio and video content. An audio input interfacereceives a digital audio signal and identifies an audio bitstream.Optionally, an audio digital decryption unit decrypts the audiobitstream. An audio decoding unit then decodes the audio bitstream. Theaudio decoding unit optionally includes a decompression componentdecompressing the audio bitstream. An audio digital to analog converterconverts the decoded audio bitstream to an analog audio signal.Optionally, an audio analog decryption unit decrypts the analog audiosignal. A video input interface receives a digital video signal andidentifies a video bitstream. Optionally, a video digital decryptionunit decrypts the video bitstream. A video decoding unit then decodesthe video bitstream. The video decoding unit optionally includes adecompression component decompressing the video bitstream. A videodigital to analog converter converts the decoded video bitstream to ananalog video signal. Optionally, a video analog decryption unit decryptsthe analog video signal. An analog transmitter then mixes the analogaudio signal and analog video signal into an analog wireless outputsignal and transmits the analog wireless output signal to the analogwireless device.

FIG. 1 is a circuit diagram of a system for broadcasting both audio andvideo to an analog device. In FIG. 1, an audio circuit 120 obtains adigital audio signal and produces an analog audio signal which can bedistributed to an analog wireline device 100 or broadcast to an analogwireless device 110. The analog wireline device 100 is, for example, anyone or more of a number of devices including, but not limited to, acassette recorder, television, video cassette recorder, amplifier, oramplified speakers. The analog wireless device 110 is, for example, anyone or more of a number of devices including, but not limited to, aradio, television, cordless telephone or wireless speakers.

The audio circuit 120 contains an audio input interface 122, an optionalaudio digital decryption unit 123, an audio decoding unit 124, an audiodigital to analog converter 126, an optional audio analog decryptionunit 127 and an audio output interface 128. One of ordinary skill in theart will implement these components using circuitry best suited to theapplication at hand. For example, each of the components may beimplemented with one or more chips or with software executed by aprocessor contained therein or in another component of the system shownin FIG. 1, such as a control unit 130, which will be described in moredetail below. The functions of these components will be explained ingreater detail with references to the flowcharts below.

Similarly, a video circuit 140 obtains a digital video signal andproduces an analog video signal which can be distributed to the analogwireline device 100 or broadcast to the analog wireless device 110. Thevideo circuit contains a video input interface 142, an optional videodigital decryption unit 143, a video decoding unit 144, a video digitalto analog converter 146, an optional video analog decryption unit 147and a video output interface 148. One of ordinary skill in the art willimplement these components using circuitry best suited to theapplication at hand. For example, each of the components may beimplemented with one or more chips or with software executed by aprocessor contained therein, or in another component of the system shownin FIG. 1, such as the control unit 130. The functions of thesecomponents will be explained in greater detail with reference to theflowcharts below.

An analog transmitter 150 mixes the analog audio signal and analog videosignal into an analog wireless output signal and transmits the analogwireless output signal to the analog wireless device 110. For example,where the analog wireless device 110 is a radio, the analog transmitter150 transmits an analog audio signal in the FM or AM band. When bothaudio and video content are present, a synchronization unit 160synchronizes processing by the audio circuit 120 and the video circuit140 to synchronize the output to the analog wireless device 110. If theaudio and video are provided as an integrated digital input signal, asplitter 170 separates the digital input signal into the digital audiosignal received by the audio circuit 120 and the digital video signalreceived by the video circuit 140.

The control unit 130 obtains input from a user and controls the audiocircuit 120 to play audio and the video circuit 140 to play video inaccordance with the user input. The control unit 130 obtains input froma user and controls the audio circuit 120 to process the digital audiosignal and the video circuit 140 to process the digital video signal inaccordance with the user input. One of ordinary skill in the art willreadily implement the control unit 130 in any of a number of differentways, depending on the environment and end device to which the system isapplied. For example, where the analog wireless device 110 is a radio,the control unit 130 can be implemented as a control panel or remotecontrol device which obtains a frequency selection from a user andcontrols the analog transmitter to transmit the analog audio signal atthe radio frequency selected by the user. The control unit could alsoobtain a selection of the AM or FM band by the user. As another example,where the analog wireless device 110 is a television, the control unit130 can be implemented as a control panel or remote control device whichobtains a channel or television frequency selection from a user andcontrols the analog transmitter to transmit the analog wireless outputsignal at the television frequency or channel selected by the user. Thecontrol unit 130 can also provide for selection from a number ofdifferent possible input sources and formats, and for selection fromamong one or more end devices.

FIG. 2 is a flowchart of the process performed by the system shown inFIG. 1. In step 205, the system obtains a digital input signal. Thedigital input signal may be an integrated audio/video signal or aseparate digital audio signal and digital video signal. If the digitalinput signal is determined in step 210 to be an integrated audio/videosignal, the splitter 170 splits the signal in step 215 into a digitalaudio signal and a digital video signal. The digital audio signal anddigital video signal are then processed in step 220 by the audio circuit120 and the video circuit 140, respectively.

FIG. 3 is a flowchart of the process performed by the audio circuit 120to process the digital audio signal in accordance with step 220. In step305, the audio input interface 122 receives the digital audio signal andidentifies an audio bitstream within the digital audio signal. Thedigital audio signal contains audio data from any of a number ofpossible sources. For example, the audio input interface 122 can receivethe digital audio signal from a network such as via the internet or anintranet. As another example, the audio input interface 122 can receivethe digital audio signal from a local storage device, such as a CD-ROM,DVD or hard disk.

As yet another example, the digital audio signal can be produced by acomputer application such as a text-to-speech application or a digitalmusical instrument.

One of ordinary skill in the art will readily implement the audio inputinterface 122 to receive a digital audio signal in any of a number ofpossible formats from any of a number of possible sources. The audioinput interface 122 can be implemented, for example, using physicallayer interface types such as USB, IEEE 1394-1995 and IEEE 802.x, andusing protocols such as HTTP, TCP/IP, and UDP/IP. Depending on thesource and format of the digital audio signal, the audio input interface122 performs other functions in addition to identifying the audiobitstream. Such functions include, but are not necessarily limited to,physical layer functions such as error correction, etc., transport layerfunctions such as device addressing, etc., session layer functions suchas content provider selection, and so forth.

If the audio bitstream is determined in step 310 to have been digitallyencrypted, the audio digital decryption unit 123 digitally decrypts theaudio bitstream in step 315. Possible applications of the inventiondescribed herein may require the digital audio signal to be digitallyencrypted so that only authorized devices can use the audio contenttherein, such as premium channels, classified information, copyprotection, and pay-per-listen content. The control unit 130 controlsthe audio digital decryption unit 123 to decrypt only authorized digitalaudio. One of ordinary skill in the art will readily implement the audiodigital decryption unit 123 utilizing available hardware, software, andso forth.

In step 320, the audio decoding unit 124 decodes the audio bitstream.One of ordinary skill in the art will implement the audio decoding unit124 based on the environment and application at hand, utilizingavailable hardware, software, etc. to decode the data based on any of anumber of possible encoding methods with which the audio bitstream hasbeen encoded. Such encoding methods include, but are not limited to,ADPCM, CD-DA, ITU G.711, G.722, G.723 & G.728, MPEG I, II & III, AC-3,AIFF, AIFC, AU, Pure Voice, Real Audio and WAV. Depending on theencoding method, data compression may also be included, in which casestep 320 includes the step of decompressing the audio bitstream and theaudio decoding unit 124 includes a decompression component.

In step 325, the audio digital to analog converter 126 converts theaudio bitstream to an analog audio signal. One of ordinary skill in theart will readily implement the audio digital to analog converter 126utilizing an available digital to analog converter. If the analog audiosignal is determined in step 330 to have been analog encrypted, then theaudio analog decryption unit 127 decrypts the analog audio signal instep 335. Possible applications of the invention described hereinrequire the analog audio signal to be analog encrypted so that onlyauthorized devices can use the analog audio or because the audio contentis copy protected. The control unit 130 controls the audio analogdecryption unit 127 to decrypt only authorized digital audio.

FIG. 4 is a flowchart of the process performed by the video circuit 140to process the digital video signal in accordance with step 220. Theprocess is essentially the same as that performed by the audio circuit120 to process the digital audio signal. In step 405, the video inputinterface 142 receives the digital video signal and identifies a videobitstream within the digital video signal. The digital video signalcontains video data from any of a number of possible sources. Forexample, the video input interface 142 can receive the digital videosignal from a network such as via the internet or an intranet. Asanother example, the video input interface 142 can receive the digitalvideo signal from a local storage device, such as a CD-ROM, DVD or harddisk. As yet another example, the digital video signal can be producedby a digital video camera.

One of ordinary skill in the art will readily implement the video inputinterface 142 to receive a digital video signal in any of a number ofpossible formats from any of a number of possible sources. The videoinput interface 142 can be implemented, for example, using physicallayer interface types such as USB, IEEE 1394-1995 and IEEE 802.x, andusing protocols such as HTTP, TCP/IP, and UDP/IP. Depending on thesource and format of the digital video signal, the video input interface142 performs other functions in addition to identifying the videobitstream. Such functions include, but are not necessarily limited to,physical layer functions such as error correction, etc., transport layerfunctions such as device addressing, etc., session layer functions suchas content provider selection, and so forth.

If the video bitstream is determined in step 410 to have been digitallyencrypted, the video digital decryption unit 143 digitally decrypts thevideo bitstream in step 415. Possible applications of the inventiondescribed herein may require the digital video signal to be digitallyencrypted so that only authorized devices can use the video contenttherein, such as premium channels, classified information, copyprotection, and pay-per-view content. The control unit 130 controls thevideo digital decryption unit 143 to decrypt only authorized digitalvideo. One of ordinary skill in the art will readily implement the videodigital decryption unit 143 utilizing available hardware, software, andso forth.

In step 420, the video decoding unit 144 decodes the video bitstream.One of ordinary skill in the art will implement the video decoding unit144 based on the environment and application at hand, utilizingavailable hardware, software, etc. to decode the data based on any of anumber of possible encoding methods with which the video bitstream hasbeen encoded. Such encoding methods include, but are not limited to, ITUH.261 & H.263, Motion JPEG, MPEG-1, MPEG-2 and MPEG-4, Cinepak,ClearVideo, Sony DV, Indeo, Real Video, Sorensen and VDOLive. Dependingon the encoding method, data compression may also be included, in whichcase step 420 includes the step of decompressing the video bitstream andthe video decoding unit 144 includes a decompression component.

In step 425, the video digital to analog converter 146 converts thevideo bitstream to an analog video signal. One of ordinary skill in theart will readily implement the video digital to analog converter 146utilizing an available digital to analog converter. If the analog videosignal is determined in step 430 to have been analog encrypted, then thevideo analog decryption unit 147 decrypts the analog video signal instep 435. Possible applications of the invention described herein mayrequire the analog video signal to be analog encrypted so that onlyauthorized devices can use the analog video or because the video contentis copy protected. The control unit 130 controls the video analogdecryption unit 147 to decrypt only authorized digital video.

Returning now to FIG. 2, upon processing the digital audio signal anddigital video signal in step 220, the system outputs in step 225 theappropriate analog signal to the end device. FIG. 5 is a flowchart ofthis output process. The system determines in step 505 whether the enddevice is an analog wireline device 100 or an analog wireless device110. If the end device is an analog wireline device 100, then the audiooutput interface 128 distributes in step 510 the analog audio signal andthe video output interface 148 distributes the analog video signal tothe analog wireline device 100 via wireline. One of ordinary skill inthe art will readily implement the audio output interface 128 and videooutput interface 148 utilizing available hardware, software, etc. toprovide the appropriately formatted wireline signals, depending on theinput format expected by the analog wireline device 100. For example,the audio output interface 128 can distribute the analog audio signal toa cassette recorder, amplifier or amplified speakers using a standardline out connection. Similarly, the video output interface 148 candistribute the analog video signal to a television or video cassetterecorder using a standard Composite Video or S-Video connection. One ofordinary skill in the art will also readily extend the implementation todistribute the analog audio signal and/or analog video signal tomultiple devices, as desired for the application at hand.

If the end device is an analog wireless device 110, then the analogtransmitter 150 mixes in step 515 the analog audio signal and the analogvideo signal to produce an analog wireless output signal and transmitsin step 520 the analog wireless output signal to the analog wirelessdevice 110. One of ordinary skill in the art will readily implement theanalog transmitter to provide the appropriately formatted wirelesssignals, depending on the input format expected by the analog wirelessdevice 110. For example, the analog transmitter 150 can transmit to aradio in a radio frequency in the AM or FM band, to a television in atelevision frequency or channel, or to wireless speakers and headphonesin the 900 Mhz frequency band. Alternatively, where the end device is awireline device that receives a transmitted signal, such as a cabletelevision, the analog transmitter 150 transmits an analog output signalto a wireline device instead of distributing the analog audio signal andthe analog video signal in step 510. One of ordinary skill in the artwill also readily extend the implementation to transmit the analog audiosignal, analog video signal or analog wireless output signal to multipledevices, as desired for the application at hand.

It should be appreciated that the invention described herein providesthe capability of playing digital audio and/or video with a devicedesigned to receive a different form of input. The present invention hasbeen described above with reference to preferred embodiments. However,those skilled in the art will recognize that changes and modificationsmay be made in these preferred embodiments without departing from thescope of the present invention. For example, one of ordinary skill inthe art will recognize circumstances where the components of the audiocircuit 120 and the video circuit 140 may be differently arranged suchthat the functions performed thereby will be performed in a differentorder, as desired. Changes and modifications which are obvious to thoseskilled in the art are intended to be included within the scope of thepresent invention.

What is claimed is:
 1. A system for broadcasting audio content of adigital audio signal to an analog wireless device, comprising: an audioinput interface receiving the digital audio signal from a plurality ofsources and identifying an audio bitstream, wherein the audio bitstreamcomprises audio data based on a plurality of encoding methodscorresponding to the plurality of sources; an audio decoding unitconnected to the audio input interface and decoding the audio bitstream;an audio decryption unit connected to the audio input interface anddecrypting only authorized audio content; an audio digital to analogconverter connected to the audio decoding unit and converting the audiobitstream to an analog audio signal; and an analog transmitter connectedto the audio digital to analog converter and transmitting the analogaudio signal to the analog wireless device.
 2. The system of claim 1,wherein the audio decryption unit comprises an audio digital decryptionunit decrypting the audio bitstream.
 3. The system of claim 1, whereinthe audio decryption unit comprises an audio analog decryption unitdecrypting the analog audio signal.
 4. The system of claim 1 wherein theaudio decryption unit employs copy protection so that only authorizeddevices can use the audio content.
 5. The system of claim 1 wherein theaudio decryption unit decrypts the audio content so that only authorizeddevices can use premium channels.
 6. The system of claim 1 wherein theaudio decryption unit decrypts the audio content so that only authorizeddevices can use pay-per-listen content.
 7. The system of claim 1 whereinthe audio decryption unit decrypts the audio content so that onlyauthorized devices can use classified information.
 8. A system forbroadcasting video content of a digital video signal to an analogwireless device, comprising: a video input interface receiving thedigital video signal from a plurality of sources and identifying a videobitstream, wherein the video bitstream comprises video data based on aplurality of encoding methods corresponding to the plurality of sources;a video decoding unit connected to the video input interface anddecoding the video bitstream; a video decryption unit connected to thevideo input interface and decrypting only authorized video; a videodigital to analog converter connected to the video decoding unit andconverting the video bitstream to an analog video signal; and an analogtransmitter connected to the video digital to analog converter andtransmitting the analog video signal to the analog wireless device. 9.The system of claim 8, wherein the video decryption unit comprises avideo digital decryption unit decrypting the video bitstream.
 10. Thesystem of claim 8, wherein the video decryption unit comprises a videoanalog decryption unit decrypting the analog video signal.
 11. Thesystem of claim 8 wherein the video decryption unit employs copyprotection so that only authorized devices can use the video content.12. The system of claim 8 wherein the video decryption unit decrypts thevideo content so that only authorized devices can use premium channels.13. The system of claim 8 wherein the video decryption unit decrypts thevideo content so that only authorized devices can use pay-per-viewcontent.
 14. The system of claim 8 wherein the video decryption unitdecrypts the video content so that only authorized devices can useclassified information.
 15. A method for broadcasting audio content of adigital audio signal to an analog wireless device, comprising the stepsof: receiving the digital audio signal from a plurality of sources andidentifying an audio bitstream, wherein the audio bitstream comprisesaudio data based on a plurality of encoding methods corresponding to theplurality of sources; decoding the audio bitstream; decrypting onlyauthorized audio-content; converting the audio bitstream to an analogaudio signal; and transmitting the analog audio signal to the analogwireless device.
 16. The method of claim 15, wherein the step ofdecrypting only authorized audio content comprises decrypting the audiobitstream.
 17. The method of claim 15, wherein the step of decryptingonly authorized audio content comprises decrypting the analog audiosignal.
 18. The method of claim 15 wherein the step of decrypting onlyauthorized audio content comprises employing copy protection so thatonly authorized devices can use the audio content.
 19. The method ofclaim 15 wherein the step of decrypting only authorized audio contentcomprises decrypting the audio content so that only authorized devicescan use premium channels.
 20. The method of claim 15 wherein the step ofdecrypting only authorized audio content comprises decrypting the audiocontent so that only authorized devices can use pay-per-listen content.21. The method of claim 15 wherein the step of decrypting onlyauthorized audio content comprises decrypting the audio content so thatonly authorized devices can use classified information.
 22. A method forbroadcasting video content of a digital video signal to an analogwireless device, comprising the steps of: receiving the digital videosignal from a plurality of sources and identifying a video bitstream,wherein the video bitstream comprises video data based on a plurality ofencoding methods corresponding to the plurality of sources; decoding thevideo bitstream; decrypting only authorized video content; convertingthe video bitstream to an analog video signal; and transmitting theanalog video signal to the analog wireless device.
 23. The method ofclaim 22, wherein the step of decrypting only authorized video contentcomprises decrypting the video bitstream.
 24. The method of claim 22,wherein the step of decrypting only authorized video content comprisesdecrypting the analog video signal.
 25. The method of claim 22 whereinthe step of decrypting only authorized video content comprises employingcopy protection so that only authorized devices can use the videocontent.
 26. The method of claim 22 wherein the step of decrypting onlyauthorized video content comprises decrypting the video content so thatonly authorized devices can use premium channels.
 27. The method ofclaim 22 wherein the step of decrypting only authorized video contentcomprises decrypting the video content so that only authorized devicescan use pay-per-view content.
 28. The method of claim 22 wherein thestep of decrypting only authorized video content comprises decryptingthe video content so that only authorized devices can use classifiedinformation.